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Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones

Transmembrane proton gradients coupled to, and maintained by, electron transport are ubiquitous sources of chemiosmotic energy in all life today, but how this system first emerged is uncertain. Here we report a model liposome system in which internal ferricyanide serves as an oxidant and external as...

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Autores principales: Milshteyn, Daniel, Cooper, George, Deamer, David
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713726/
https://www.ncbi.nlm.nih.gov/pubmed/31462644
http://dx.doi.org/10.1038/s41598-019-48328-5
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author Milshteyn, Daniel
Cooper, George
Deamer, David
author_facet Milshteyn, Daniel
Cooper, George
Deamer, David
author_sort Milshteyn, Daniel
collection PubMed
description Transmembrane proton gradients coupled to, and maintained by, electron transport are ubiquitous sources of chemiosmotic energy in all life today, but how this system first emerged is uncertain. Here we report a model liposome system in which internal ferricyanide serves as an oxidant and external ascorbate or dithionite provide a source of electrons to electron carriers embedded in liposome membranes. Quinones linked the donor to the acceptor in a coupled redox reaction that released protons into the vesicle internal volume as electrons were transported across the membranes, thereby producing substantial pH gradients. Using this system, we found that one or more quinones in extracts from carbonaceous meteorites could serve as coupling agents and that substantial pH gradients developed in the acidic interior of liposomes. If amphiphilic compounds present on the prebiotic Earth assembled into membranous compartments that separate reduced solutes in the external medium from an encapsulated acceptor, quinones can mediate electron and proton transport across the membranes, thereby providing a source of chemiosmotic energy for primitive metabolic reactions.
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spelling pubmed-67137262019-09-13 Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones Milshteyn, Daniel Cooper, George Deamer, David Sci Rep Article Transmembrane proton gradients coupled to, and maintained by, electron transport are ubiquitous sources of chemiosmotic energy in all life today, but how this system first emerged is uncertain. Here we report a model liposome system in which internal ferricyanide serves as an oxidant and external ascorbate or dithionite provide a source of electrons to electron carriers embedded in liposome membranes. Quinones linked the donor to the acceptor in a coupled redox reaction that released protons into the vesicle internal volume as electrons were transported across the membranes, thereby producing substantial pH gradients. Using this system, we found that one or more quinones in extracts from carbonaceous meteorites could serve as coupling agents and that substantial pH gradients developed in the acidic interior of liposomes. If amphiphilic compounds present on the prebiotic Earth assembled into membranous compartments that separate reduced solutes in the external medium from an encapsulated acceptor, quinones can mediate electron and proton transport across the membranes, thereby providing a source of chemiosmotic energy for primitive metabolic reactions. Nature Publishing Group UK 2019-08-28 /pmc/articles/PMC6713726/ /pubmed/31462644 http://dx.doi.org/10.1038/s41598-019-48328-5 Text en © The Author(s) 2019 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Milshteyn, Daniel
Cooper, George
Deamer, David
Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title_full Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title_fullStr Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title_full_unstemmed Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title_short Chemiosmotic energy for primitive cellular life: Proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
title_sort chemiosmotic energy for primitive cellular life: proton gradients are generated across lipid membranes by redox reactions coupled to meteoritic quinones
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713726/
https://www.ncbi.nlm.nih.gov/pubmed/31462644
http://dx.doi.org/10.1038/s41598-019-48328-5
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